Higher education institutions (HEIs) operate at the intersection of formal rules, policies, and complex informal social dynamics. This chapter explores the interplay between agency, as the capacity of individuals and groups to act, and structure, as the institutional frameworks and constraints within which they operate. This is considered in the context of institutional change in higher education, which emphasises formal governance and policy, as well as informal attributes and power relations that persistently influence outcomes. Understanding this duality is essential for unpacking the processes of formation, endurance, and transformation within higher education institutions. The chapter draws on key theoretical insights and empirical examples from South African universities to demonstrate how agency and structure mutually reinforce and contest each other. It argues that institutional change cannot be understood solely from a structural or agency perspective, but requires a nuanced synthesis of both.